<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS常用值</title>
    <style>
        h1 {
            color: red;
            color: rgb(255,0,0);
            color: rgb(0,255,255);
            color: rgb(0,255,0);
            color: rgb(255,0,255);
            color: rgb(0,0,255);
            color: rgb(255,255,0);
            color: rgb(128,128,128);
            color: rgb(255,255,255);
            color: rgb(0,0,0);

            color: #ff0000;
            color: #00ff00;
            color: #00f;
            color: #fff;
            color: #000;
            color: #808080;

            color: rgba(255,0,0,0.8);
            color: rgba(255,0,0,0.6);
            color: rgba(255,0,0,0.3);
            color: rgba(255,0,0,0);
            color: rgba(255,0,0,1);
        }

        .d1 {
            width: 500px;
            height: 300px;
            background-image:linear-gradient(45deg,#ff0000,orange,pink,cyan);
        }
        .d2 {
            width: 50px;
            height: 100px;
            background-color: #000;
            background-image: url(img/mr.png);
            background-size: 50px 100px;
        }

        .d3 {
            width: 500px;
            height: 300px;
            border: 5px solid #f00;
            background-image: url(img/mr.png);
            background-repeat: no-repeat;
            background-position: 0 0;
            background-position: 50px 0;
            background-position: 0px 100px;
            background-position: -50px -50px;
            background-position: left top;
            background-position: center;
            background-position: 50% 50%;

        }

    </style>
</head>
<body>
    <h1>测试颜色</h1>
    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>
</body>
</html>